feat(bb-avm-sim): a wasm backend for the bb-avm-sim package by charlielye · Pull Request #25670 · AztecProtocol/aztec-packages

charlielye · 2026-10-20T11:19:35Z

Stacked on #25433 (the wasm transport in ipc-runtime) and #25669 (wasm exception handling, node 26, wasi-sdk 34), which is merged in here. Review those first; this PR is the last two commits.

Why

@aztec-foundation/bb-avm-sim could only spawn the native bb-avm-sim binary. With exceptions now on in wasm, the AVM simulator builds for wasm, so the package can run it in-process the way bb.js-api runs bb: the binary in node, the wasm module in browsers. This is the first step towards running public simulation in a browser node.

What changes

C++ (barretenberg/avm)

avm_schema.json is now also generated with --ffi, giving the in-process entry avm_ipc_ffi_entry.
New avm_ffi module: that entry, its dispatcher context and a shared simulate_with_hints. It builds natively and for wasm.
bb-avm-sim.wasm (1.6 MB): a WASI reactor over avm_ffi, built by the wasm preset like wsdb-ref's module.
It has no route to world state or contract data yet, so it serves SimulateWithHints (whose hints answer every read) and answers Simulate with an error. Reaching wsdb and cdb from wasm is the host_call follow-up.
The native binary's --wsdb and --cdb are now optional. Without them it serves SimulateWithHints alone, on the same terms as the wasm module.
The wasm build adds aztec, world_state_reference, vm2 (the simulator only; the wasm presets set AVM off) and avm. It brings the simulator's wasm32 fixes: a 32-bit shift in contract_crypto and size_t narrowing in the indexed trees.

Tests

avm_ffi_tests calls the FFI entry with vm2's minimal_tx fixture, embedded at configure time, and checks the result against the public inputs the fixture carries (gas, fee, revert status, effect counts). It also checks that simulator exceptions are caught, that a malformed input gets an error and the next call still works, and that Simulate answers with an error.
- Runs natively with the other *_tests, and under wasmtime from the single-threaded build (test_cmds_wasm, make bb-cpp-wasm-tests).
- bb links wasm with --import-memory. The wasmtime CLI only supplies that memory under wasi-threads, so wasmtime.sh gains SINGLE_THREADED=1, which preloads a one-line module exporting it (scripts/wasm_env_memory.wat).
barretenberg/ts/scripts/bb_avm_sim.test.mjs (make bb-avm-sim-tests) runs one transaction through the spawned binary, the wasm worker and the synchronous wasm service, and requires the same result, matching the fixture's public inputs. Errors come back as AvmError and the service keeps answering.

Package and build

The package is generated with --package-transports uds,wasm --package-wasm-module bb-avm-sim.wasm. bootstrap.sh copies the module in for builds and releases, and bb-avm-sim now depends on bb-cpp-wasm.
ipc-runtime's prepare_arch_packages now handles a string bin. yarn install rewrites the generated one-entry bin map to that form, and the script then staged the native binary as a file named 0.

Testing

avm_ffi_tests: 4/4 natively (clang20), 4/4 under wasmtime 46 from the single-threaded build and from the threads build.
bb_avm_sim.test.mjs on node 26: 4/4 (binary, wasm worker, sync wasm).
Not run: a browser test of the package, and the Makefile targets end to end in CI.

🤖 Generated with Claude Code

https://claude.ai/code/session_01G5s7nEWrYapDK2CWpEzcAf

@TomAFrench

Moves `noir/noir-repo` from `v1.0.0-rc.3` (`5a7ee9bf`) to `v1.0.0-rc.5` (`0f759ffe`). Produced by `noir/scripts/bump_noir_compiler.sh v1.0.0-rc.5`: the submodule pointer and `avm-transpiler/Cargo.lock` (noir path packages only). `noir-projects/fnd` formatting with the rc.5 `nargo` produced no changes. Upstream range: noir-lang/noir@v1.0.0-rc.3...v1.0.0-rc.5 (162 commits, none marked breaking) ### Labs patch `0019` rc.5's `nargo expand` prints associated-constant array lengths in contract interface stubs as written rather than folded (`[Field; (16 * 20) + 1]` and `Serialize<N = (16 * 20) + 1>` instead of `[Field; 321]`). Five `contract-snapshots` expand snapshots (`amm`, `token`, `avm_gadgets_test`, `public_fns_with_emit_repro`, `storage_proof_test`) are regenerated for that. It is a test-only change, carried as a labs patch. Notable upstream changes that could move artifacts here: - Many `fix(frontend)` trait-constraint/associated-type resolution fixes (e.g. [noir-lang/noir#13982](noir-lang/noir#13982), [#13971](noir-lang/noir#13971), [#13939](noir-lang/noir#13939)). - `fix(ssa)`: Brillig missing-constraints check refinements ([#13893](noir-lang/noir#13893), [#13886](noir-lang/noir#13886), [#13879](noir-lang/noir#13879), [#13880](noir-lang/noir#13880)). - `fix(acir)`: constant-length `vector_push_back` growth ([#13945](noir-lang/noir#13945)) and predicate-zero blackbox calls in ACIR gen ([#13965](noir-lang/noir#13965)). Checked locally: `nargo` and `avm-transpiler` build, the fnd formatter makes no changes, `contract-snapshots` passes (61/61) against this tree with rc.5, and `labs-patches/bootstrap.sh check` applies the series cleanly. --- *Created by [claudebox](https://claudebox.work/v2/sessions/be9a837cc5ef642a/jobs/1) · group: `slackbot` · requested by Tom (@TomAFrench) · [Slack thread](https://aztecfoundation.slack.com/archives/D0B586H14KG/p1792071360555509?thread_ts=1792071360.555509&cid=D0B586H14KG)*

Add `v6` to the nightly release tag matrix so it gets `v6.0.0-nightly.<date>` tags alongside `next` and `v5-next`. The release line is `v6` (there is no `v6-next`), and its manifest version does not collide with the other branches' tags.

Every bb wasm build compiled with -fno-exceptions, so throw_or_abort called out to the JavaScript environment, whose throw unwound the module without running catch blocks or destructors, and the AVM simulator (which signals exceptional halts with C++ exceptions) could not build for wasm at all. wasi-sdk 33+ ships a sysroot with a C++ exception runtime, so the wasm and wasm-threads builds now use standard (exnref) wasm exception handling, and the toolchains move to versions that run it unflagged. bb wasm - arch.cmake: -fwasm-exceptions -mllvm -wasm-use-legacy-eh=false, linked with -lunwind, in place of -fno-exceptions. The wasm preset drops -DBB_NO_EXCEPTIONS and sets AVM off. - throw_or_abort throws std::runtime_error inside the module in wasm builds with exceptions, so bbapi answers with an ErrorResponse, as it does natively. bb.js's exception test now also checks the module no longer aborts (it fails on the old wasm). - The wasm build adds aztec, world_state_reference, vm2 (vm2_sim only) and crypto/merkle_tree, and the wasm build preset builds vm2_sim_smoke. That runs one hinted public transaction (vm2/testing/minimal_tx.testdata.bin) through AvmSimAPI::simulate_with_hinted_dbs after checking a TagMismatchException is caught; scripts/vm2_sim_smoke_test.sh runs it natively and in wasm under node and requires identical results. It runs in the default bb test_cmds. - wasm32 fixes in the simulator and the in-memory trees, where size_t is 32-bit: contract_crypto shifted a size_t by 32, which is undefined on wasm32 and would corrupt the first bytecode field; index_t to size_t casts in the in-memory indexed trees and their callers; ptrdiff_t in to_radix. - LLVM 23 (wasi-sdk 34) fixes: wasm32-wasip1-threads in place of the removed wasm32-wasi-threads target; missing <algorithm> and <cstdlib> includes; static function templates in headers made inline (-Wunused-template); -Wno-c2y-extensions for google-benchmark, which builds with -pedantic-errors and uses __COUNTER__. - barretenberg.wasm grows 5% (17.17 MB to 18.03 MB), 3.4% gzipped (3.88 MB to 4.01 MB). UltraHonk 2^20 proving under wasmtime showed no difference beyond noise. Toolchains (build image and scripts/setup-container.sh) - node 24.15.0 to 26.12.0 (.nvmrc, bootstrap's expected minimum and install_node). Node 26 removed --experimental-transform-types; the ipc-codegen callers only need type stripping, so it is dropped. - wasi-sdk 27 to 34 at /opt/wasi-sdk. - wasmtime 20.0.2 to 46.0.3, the last release with wasi-threads (-Sthreads), which the threaded wasm tests and benchmarks use. Its invocations add -Wexceptions=y and -Wshared-memory=y. - playwright 1.49 to 1.63.0 (Chromium 153; exnref is unflagged from Chrome 137), in the image and headless-test. The CI image is not redeployed here. Until it is, the root bootstrap's transitional_toolchain_upgrade (run by prep and check, in CI or the devbox) installs wasi-sdk 34 at /opt/wasi-sdk and node, wasmtime and playwright's chromium under $HOME, passing PATH and PLAYWRIGHT_BROWSERS_PATH through to isolated test containers. In devbox:3.1 it takes about 36s the first time and 3s after. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G5s7nEWrYapDK2CWpEzcAf

This PR keeps to the toolchain and exception handling. The vm2_sim_smoke program, its test, the vm2-in-wasm CMake and the wasm32 fixes in the simulator move to the PR that builds bb-avm-sim as a wasm module for its generated package. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G5s7nEWrYapDK2CWpEzcAf

On this base bb's wasm env exits the module on throw_or_abort, and bb.js pinned a thrown error as a plain Error on wasm. With exceptions it is a BbError on both backends, and the module keeps answering. Drops the node 26-removed --experimental-transform-types from the bb.js-api codegen. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G5s7nEWrYapDK2CWpEzcAf

bb-avm-sim.wasm is the AVM simulator as a WASI reactor exporting the generated FFI entry (avm_ipc_ffi_entry), so @aztec-foundation/bb-avm-sim runs the spawned binary in node and the wasm module in browsers, as bb.js-api does for bb. The module has no route to world state or contract data yet, so it serves SimulateWithHints and answers Simulate with an error. bb-avm-sim's --wsdb and --cdb become optional on the same terms. - avm_ffi: the FFI entry and its context, built natively and for wasm. avm_ffi_tests calls the entry with vm2's minimal_tx fixture and checks the result against the public inputs it carries; it runs natively and, from the threads build, under wasmtime like ecc_tests. - The wasm build adds aztec, world_state_reference, vm2 (the simulator alone, AVM off) and avm, with the simulator's wasm32 fixes (a 32-bit shift in contract_crypto, size_t narrowing in the indexed trees). - The package's test runs one transaction through the binary, the wasm worker and the synchronous wasm service and requires the same result. - ipc-runtime's prepare_arch_packages reads a string bin, the form yarn rewrites the generated one-entry bin map to on install; it staged the binary as a file named 0. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G5s7nEWrYapDK2CWpEzcAf

bb links its wasm with --import-memory. Under wasi-threads wasmtime makes that memory, but for a single-threaded build the CLI fills no env.memory, so the tests ran from the threads build. wasmtime.sh's SINGLE_THREADED=1 now preloads a module exporting one, and avm_ffi_tests runs from the build bb-avm-sim.wasm comes from. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01G5s7nEWrYapDK2CWpEzcAf

socket-security · 2026-10-20T11:20:46Z

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	npm/playwright@1.49.0 ⏵ 1.63.0	⁺¹	⁺¹⁶		⁺¹	^-19

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socket-security · 2026-10-20T11:20:48Z

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Review the following alerts detected in dependencies.

According to your organization's Security Policy, it is recommended to resolve "Warn" alerts. Learn more about Socket for GitHub.

Priority	Alert (click "▶" to expand/collapse)	Action
	Potential security risk (AI signal): npm `playwright-core` is 70.0% likely risky Notes: No evidence of obfuscated or overtly malicious logic (no persistence, exfiltration, or credential theft) appears in the provided snippet. However, it implements a high-risk supply-chain pattern: it downloads an MSI from a URL provided at runtime and installs it silently via msiexec without any integrity or origin verification. If an attacker can influence $args[0] or the referenced endpoint, this script can facilitate arbitrary MSI payload execution on the host. Confidence: 0.70 Severity: 0.72 From: barretenberg/acir_tests/headless-test/package.json → `npm/playwright@1.63.0` → `npm/playwright-core@1.63.0` ℹ Read more on: This package \| This alert \| What are AI-detected potential security risks? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at `support@socket.dev`. Suggestion: An AI system identified potential security problems in this package. It is advised to review the package thoroughly and assess the potential risks before installation. You may also consider reporting the issue to the package maintainer or seeking alternative solutions with a stronger security posture. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment `@SocketSecurity ignore npm/playwright-core@1.63.0`. You can also ignore all packages with `@SocketSecurity ignore-all`. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.	Warn
	Potential security risk (AI signal): npm `playwright-core` is 76.0% likely risky Notes: This module is a straightforward installer wrapper, but it has a high supply-chain trust boundary risk: it downloads an MSI from a caller-provided URL and silently executes it via msiexec without any integrity/signature validation or URL allowlisting. There is no clear evidence of hidden malware in the visible code, but the execution pattern can enable malicious installer delivery if the URL/contents are compromised or attacker-controlled. Confidence: 0.76 Severity: 0.74 From: barretenberg/acir_tests/headless-test/package.json → `npm/playwright@1.63.0` → `npm/playwright-core@1.63.0` ℹ Read more on: This package \| This alert \| What are AI-detected potential security risks? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at `support@socket.dev`. Suggestion: An AI system identified potential security problems in this package. It is advised to review the package thoroughly and assess the potential risks before installation. You may also consider reporting the issue to the package maintainer or seeking alternative solutions with a stronger security posture. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment `@SocketSecurity ignore npm/playwright-core@1.63.0`. You can also ignore all packages with `@SocketSecurity ignore-all`. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.	Warn
	Potential security risk (AI signal): npm `playwright-core` is 78.0% likely risky Notes: This module is a generic “download-and-silent-install MSI” bootstrapper where the critical control point (the download URL) is fully caller-controlled and the fragment lacks any integrity/signature verification of the downloaded MSI before executing it via msiexec. While there is no explicit backdoor/exfiltration code in the fragment, the combination of (a) arbitrary remote MSI acquisition and (b) silent installer execution makes it a high-risk supply-chain pattern if $args[0] can be influenced or if download provenance cannot be guaranteed externally. Confidence: 0.78 Severity: 0.78 From: barretenberg/acir_tests/headless-test/package.json → `npm/playwright@1.63.0` → `npm/playwright-core@1.63.0` ℹ Read more on: This package \| This alert \| What are AI-detected potential security risks? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at `support@socket.dev`. Suggestion: An AI system identified potential security problems in this package. It is advised to review the package thoroughly and assess the potential risks before installation. You may also consider reporting the issue to the package maintainer or seeking alternative solutions with a stronger security posture. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment `@SocketSecurity ignore npm/playwright-core@1.63.0`. You can also ignore all packages with `@SocketSecurity ignore-all`. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.	Warn

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AztecBot and others added 7 commits October 16, 2026 13:38

chore: cut nightly release tags for v6 (#25657)

cfdcaf1

Add `v6` to the nightly release tag matrix so it gets `v6.0.0-nightly.<date>` tags alongside `next` and `v5-next`. The release line is `v6` (there is no `v6-next`), and its manifest version does not collide with the other branches' tags.

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feat(bb-avm-sim): a wasm backend for the bb-avm-sim package - #25670

feat(bb-avm-sim): a wasm backend for the bb-avm-sim package#25670
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charlielye commented Oct 20, 2026

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